APMA 3120 Chapter Notes - Chapter 3-4: Simple Random Sample, Dependent And Independent Variables, Confounding
18 Feb 2016
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Chapter 3: gathering useful data: simple random sample: easiest way to guarantee that the sample truly represents the population by giving every possible group of a given size has same chance of selection. Double-blinding is the simplest way to avoid this pitfall. no treatment is imposed by researchers, type of observational study, not an experiment. Chapter 4: sampling surveys and how to ask questions a. Response variable refers: a scatterplot is the most useful display technique for the relationship between two quantitative variables. We plot yi corresponding to the xi each individual i. , values of the response variable, along the vertical axis, , values of the explanatory variable, along the horizontal axis for: direction: same for above-average values of height and shoe-size. If large values of one variable tend to occur with small values of the other negative association: form (linear, not curved) and presence of outliers/extreme values, strength: relationship with higher correlation coefficients are stronger l.
